Gaza: A rocket fired from Gaza hit a petrol station in southern Israel on Friday, causing a huge explosion and injuring three people, the army and medics said.

"A barrage of rockets was fired at Ashdod, one of which hit a gas station causing massive damage," a statement from the army said.

Medics said three people had been taken to hospital, including one who was very seriously hurt.

"Three people were injured, one very seriously," emergency services spokesman Eli Bin told public radio of the incident, which occurred in the southern port city of Ashdod, 28 kilometres (17 miles) north of Gaza.

A large fire was raging at the site, with emergency teams trying to control the blaze, medics said.